Diet Drinks Won't Protect Heart Health Any Better Than Sugary Drinks: Study

A new study suggests that artificially sweetened (often called "diet") beverages might not be a healthy substitute for sugary drinks—at least in terms of cardiovascular health. 

The research, published in The Journal of the American College of Cardiology on Tuesday, highlights a potential risk to heart health from consuming artificial sweeteners.

The researchers evaluated more than 100,000 participants who did not have known cardiovascular disease at the time of study enrollment. Each participant was asked to complete a web-based survey every six months. The survey asked them to record how much of any beverage containing 5% sugar or artificial sweeteners that they consumed as part of a 24-hour dietary record.

Based on their responses to the survey, the participants were divided into three groups: high consumers, low consumers, and no consumers.

The researchers found that the high consumers of both sugary drinks or artificially sweetened beverages demonstrated an increased risk of stroke, mini-stroke, heart attack, or heart blockage that required surgery.

It wasn't just high-consumers that were at increased risk: The participants who were classified as low consumers (an average intake of 40 to 46.7 milliliters (mL), or less than ¼ of a can of soda) were found to have a greater risk of cardiovascular health problems than non-consumers.  

“The exact reason why and how these nutritional changes had an impact on cardiovascular health is not clear from this study," Roopa Rao, MD, a heart failure transplant cardiologist at Indiana University Health, tells Verywell. "However, there is an association of artificial sweeteners causing changes to gut microbiota and increasing glucose intolerance."

What Are Artificial Sweeteners?

From sucralose to acesulfame potassium, artificial sweeteners are found in drinks, candy, and even cereal. The flavorings give a product a sweet taste without adding calories as regular sugar does.

“Although [the] Food and Drug Administration (FDA) and World Health Organization (WHO) approved the use of limited amounts of artificial sweeteners, there are reports of the negative impact of artificial sweeteners on the body,” says Rao, who was not part of the study.

“Artificial sweeteners are typically hundreds of times sweeter than regular table sugar, and they are metabolized differently by the body,” Sarah Schlichter, MPH, RDN, registered dietitian and blogger at BucketListTummy.com tells Verywell. “As dietitians, we want to help consumers consume fewer added sugars, but when it comes to artificial sweeteners, there is still a lot we don't quite know yet.” 

The Problem With Artificial Sweeteners

Many experts believe that consuming large quantities of certain artificial sweeteners contributes to metabolic syndrome and might be driving the obesity epidemic. Some research has suggested that artificial sweeteners may change the host microbiome and lead to decreased satiety. Some artificial sweeteners have been associated with increased caloric consumption and weight gain. 

The results from one systematic review and meta-analysis that evaluated 30 cohort studies indicated that the routine intake of nonnutritive sweeteners could be associated with increased body mass index (BMI) and cardiometabolic risk.

Experts also point to other potential risks associated with consuming artificial sweeteners. “Since artificial sweeteners are much sweeter than sugar, they may leave consumers craving more sweetness and can displace other nutritious whole foods," says Schlichter, adding that people sometimes overcompensate with other foods because of the empty calories they've previously consumed.

"While the occasional diet soft drink or consumption of artificial sweeteners likely won't pose a risk for most people, consumers should try to avoid relying solely on artificial sweeteners or excessive consumption of them," she says.

How Much Sugar Is Safe?

“According to the American Heart Association, added sugar should be limited to no more than 100 calories per day, which is about 6 teaspoons, or 25 grams, for most assigned female at birth," Rao says. "For people assigned male at birth, no more than 150 calories a day, which is about 9 teaspoons of sugar or 38 grams per day."

Consuming too many added sugars can contribute to poor health outcomes over time, including:

• Cardiovascular disease (CVD)
• Fatty liver
• Insulin resistance and type 2 diabetes
• Metabolic syndrome and weight gain

If you find yourself craving a sweet drink, look for one that does not contain added sugars. Remember that added sugars are not just table sugar—ingredients like honey, maple syrup, and corn syrup are also added sugars.

Best Beverages for Cardiovascular Health

The research does not say whether or not consuming artificial sweeteners and sugar definitively causes negative cardiovascular outcomes. Instead, the findings imply there is an association.

To support your overall health and wellness goals and potentially protect your heart, plain old water is your best bet for a beverage choice—it's calorie-free, sugar-free, and artificial sweetener-free. 

Try sparkling water or water infused with fruit or herbs or a little taste variety without added sugar or artificial sweeteners. Just let some fresh fruit, such as cranberries or citrus, steep in your water for a few hours to create a refreshing beverage with a hint of flavor and no added sugar.

If you want something warm and soothing, trying a cup of tea for a cozy alternative that research has shown might support your cardiovascular health. 

Remember that limiting sugary drinks will support your wellness best if you're also practicing other heart-healthy diet and exercise habits.